3-Ammonio-4-hydroxybenzoate monohydrate

The title compound, C7H7NO3·H2O, which crystallized as a hydrate, was obtained from an extraction of the plant species Saussurea atkinsonii of the asteraceae family collected from the hilly area (Ayubia) of Pakistan during the flowering season. The dihedral angle between the benzene ring and the carboxylate group is 25.64 (5)°. In the crystal, the packing is consolidated by N—H⋯O and O—H⋯O hydrogen bonds, as well as weak aromatic π–π stacking [centroid–centroid separation = 3.9365 (9) Å] and C=O⋯π interactions.

The title compound, C 7 H 7 NO 3 ÁH 2 O, which crystallized as a hydrate, was obtained from an extraction of the plant species Saussurea atkinsonii of the asteraceae family collected from the hilly area (Ayubia) of Pakistan during the flowering season. The dihedral angle between the benzene ring and the carboxylate group is 25.64 (5) . In the crystal, the packing is consolidated by N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds, as well as weak aromaticstacking [centroid-centroid separation = 3.9365 (9) Å ] and C OÁ Á Á interactions.
SU greatfully acknowledges the Higher Education Commission, Islamabad, Pakistan, for providing a Scholarship under the Indigenous PhD Program (PIN 042-121314-PS2-287).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB2969).  (Fig. 1), is an extract of it in chloroform and methanol. The study of its bio-activity is in progress.

Structure Reports Online
The crystal structure of (II) (4-vinylphenyl 3-amino-4-hydroxybenzoate or bagremycin A (Bertasso et al., 2001), has been reported which contains the aromatic ring along with heavy atoms of the substituants of (I). In the title compound, the bond distances and bond angles are within normal ranges (Allen et al., 1987). The benzene ring A (C1-C6) is planar and is oriented at a dihedral angle of 25.64 (5)° with the CO 2 group. The N-atom of ammonium is in plane of the ring A, whereas the O-atom of hydroxy group is at a distance of -0.0580 (21) Å from the same.
There exist intensive intermolecular H-bonding (Table 1), resulting in three-dimensional polymeric network. There also exist CgA···CgA i [symmetry code i = 1 -x, 1 -y, -z] interaction at a distance of 3.9365 (9) Å, where CgA is the centroid of aromatic ring. The molecules may also be stabilized due to C==O···π interaction (Table 1).

Experimental
The Specie Saussurea atkinsonii of asteraceae family was dried inside room for 20-25 days as a whole and grinded. The extract was obtained using soxhlet apparatus in 50% chloroform and 50% methanol and it was subjected to isolation by performing column chromatography and thin layer chromatography. The extract obtained was recrystallized from methanol and light brown rods of (I) were obtained. The water found in the structure was presumably incorporated from the atomsphere.

Refinement
The coordinates of H-atoms of hydroxy, ammonium moiety and water molecule were refined. The other H-atoms were positioned geometrically, with C-H = 0.93 Å for aromatic type and constrained to ride on their parent atoms, with U iso (H) = 1.2U eq (C, N, O). Fig. 1. View of (I) with displacement ellipsoids drawn at the 50% probability level. H-atoms are shown by small circles of arbitrary radius. Fig. 2. The partial packing of (I), showing that molecules form three-dimensional polymeric network.

Special details
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and tor-

sion angles
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.